Impermeable surfaces definition
Impermeable surfaces means a surface which that does not allow natural percolation of water into the ground at a rate that avoids ponding or runoff; and includes roofs, roads, footpaths, paving including proprietary pavers, decking that does not allow water to drain through to a permeable surface, swimming pools, patios gobi- blocks, grasscrete, metalled driveways, highly compacted soils, hard surfaced materials, and other similar materials. but excludes wooden decks with spacing between boards of 4mm or more, where water is allowed to drain through to a permeable surface below the deck.